diff --git a/drivers/media/video/gspca/zc3xx.c b/drivers/media/video/gspca/zc3xx.c
index 3c6db02fe74bc900db5ab72acba1d92f0a857ef1..54735dd61bb8569d954aed7f14703f9c7832b176 100644
--- a/drivers/media/video/gspca/zc3xx.c
+++ b/drivers/media/video/gspca/zc3xx.c
@@ -5921,22 +5921,8 @@ static void setexposure(struct gspca_dev *gspca_dev)
 static void setquality(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
-	s8 reg07;
-
 	jpeg_set_qual(sd->jpeg_hdr, jpeg_qual[sd->reg08 >> 1]);
-
-	reg07 = 0;
-	switch (sd->sensor) {
-	case SENSOR_OV7620:
-		reg07 = 0x30;
-		break;
-	case SENSOR_HV7131R:
-	case SENSOR_PAS202B:
-		return;			/* done by work queue */
-	}
 	reg_w(gspca_dev, sd->reg08, ZC3XX_R008_CLOCKSETTING);
-	if (reg07 != 0)
-		reg_w(gspca_dev, reg07, 0x0007);
 }
 
 /* Matches the sensor's internal frame rate to the lighting frequency.
@@ -6070,110 +6056,63 @@ static void setautogain(struct gspca_dev *gspca_dev)
 	reg_w(gspca_dev, autoval, 0x0180);
 }
 
-/* update the transfer parameters */
-/* This function is executed from a work queue. */
-/* The exact use of the bridge registers 07 and 08 is not known.
- * The following algorithm has been adapted from ms-win traces */
+/*
+ * Update the transfer parameters.
+ * This function is executed from a work queue.
+ */
 static void transfer_update(struct work_struct *work)
 {
 	struct sd *sd = container_of(work, struct sd, work);
 	struct gspca_dev *gspca_dev = &sd->gspca_dev;
 	int change, good;
-	u8 reg07, qual, reg11;
+	u8 reg07, reg11;
 
-	/* synchronize with the main driver and initialize the registers */
-	mutex_lock(&gspca_dev->usb_lock);
-	reg07 = 0;					/* max */
-	qual = sd->reg08 >> 1;
-	reg_w(gspca_dev, reg07, 0x0007);
-	reg_w(gspca_dev, sd->reg08, ZC3XX_R008_CLOCKSETTING);
-	mutex_unlock(&gspca_dev->usb_lock);
+	/* reg07 gets set to 0 by sd_start before starting us */
+	reg07 = 0;
 
 	good = 0;
 	for (;;) {
 		msleep(100);
 
-		/* get the transfer status */
-		/* the bit 0 of the bridge register 11 indicates overflow */
 		mutex_lock(&gspca_dev->usb_lock);
 		if (gspca_dev->frozen || !gspca_dev->dev ||
 					 !gspca_dev->streaming)
 			goto err;
+
+		/* Bit 0 of register 11 indicates FIFO overflow */
+		gspca_dev->usb_err = 0;
 		reg11 = reg_r(gspca_dev, 0x0011);
-		if (gspca_dev->usb_err < 0
-		 || !gspca_dev->present || !gspca_dev->streaming)
+		if (gspca_dev->usb_err)
 			goto err;
 
 		change = reg11 & 0x01;
 		if (change) {				/* overflow */
-			switch (reg07) {
-			case 0:				/* max */
-				reg07 = sd->sensor == SENSOR_HV7131R
-						? 0x30 : 0x32;
-				if (qual != 0) {
-					change = 3;
-					qual--;
-				}
-				break;
-			case 0x32:
-				reg07 -= 4;
-				break;
-			default:
-				reg07 -= 2;
-				break;
-			case 2:
-				change = 0;		/* already min */
-				break;
-			}
 			good = 0;
+
+			if (reg07 == 0) /* Bit Rate Control not enabled? */
+				reg07 = 0x32; /* Allow 98 bytes / unit */
+			else if (reg07 > 2)
+				reg07 -= 2; /* Decrease allowed bytes / unit */
+			else
+				change = 0;
 		} else {				/* no overflow */
-			if (reg07 != 0) {		/* if not max */
-				good++;
-				if (good >= 10) {
-					good = 0;
+			good++;
+			if (good >= 10) {
+				good = 0;
+				if (reg07) { /* BRC enabled? */
 					change = 1;
-					reg07 += 2;
-					switch (reg07) {
-					case 0x30:
-						if (sd->sensor == SENSOR_PAS202B)
-							reg07 += 2;
-						break;
-					case 0x32:
-					case 0x34:
+					if (reg07 < 0x32)
+						reg07 += 2;
+					else
 						reg07 = 0;
-						break;
-					}
-				}
-			} else {			/* reg07 max */
-				if (qual < sizeof jpeg_qual - 1) {
-					good++;
-					if (good > 10) {
-						qual++;
-						change = 2;
-					}
 				}
 			}
 		}
 		if (change) {
-			if (change & 1) {
-				reg_w(gspca_dev, reg07, 0x0007);
-				if (gspca_dev->usb_err < 0
-				 || !gspca_dev->present
-				 || !gspca_dev->streaming)
-					goto err;
-			}
-			if (change & 2) {
-				sd->reg08 = (qual << 1) | 1;
-				reg_w(gspca_dev, sd->reg08,
-						ZC3XX_R008_CLOCKSETTING);
-				if (gspca_dev->usb_err < 0
-				 || !gspca_dev->present
-				 || !gspca_dev->streaming)
-					goto err;
-				sd->ctrls[QUALITY].val = jpeg_qual[qual];
-				jpeg_set_qual(sd->jpeg_hdr,
-						jpeg_qual[qual]);
-			}
+			gspca_dev->usb_err = 0;
+			reg_w(gspca_dev, reg07, 0x0007);
+			if (gspca_dev->usb_err)
+				goto err;
 		}
 		mutex_unlock(&gspca_dev->usb_lock);
 	}
@@ -6721,14 +6660,10 @@ static int sd_init(struct gspca_dev *gspca_dev)
 
 	switch (sd->sensor) {
 	case SENSOR_HV7131R:
-		gspca_dev->ctrl_dis = (1 << QUALITY);
 		break;
 	case SENSOR_OV7630C:
 		gspca_dev->ctrl_dis = (1 << LIGHTFREQ) | (1 << EXPOSURE);
 		break;
-	case SENSOR_PAS202B:
-		gspca_dev->ctrl_dis = (1 << QUALITY) | (1 << EXPOSURE);
-		break;
 	default:
 		gspca_dev->ctrl_dis = (1 << EXPOSURE);
 		break;
@@ -6743,6 +6678,13 @@ static int sd_init(struct gspca_dev *gspca_dev)
 	return gspca_dev->usb_err;
 }
 
+static int sd_pre_start(struct gspca_dev *gspca_dev)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+	gspca_dev->cam.needs_full_bandwidth = (sd->reg08 >= 4) ? 1 : 0;
+	return 0;
+}
+
 static int sd_start(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
@@ -6868,6 +6810,8 @@ static int sd_start(struct gspca_dev *gspca_dev)
 		break;
 	}
 	setquality(gspca_dev);
+	/* Start with BRC disabled, transfer_update will enable it if needed */
+	reg_w(gspca_dev, 0x00, 0x0007);
 	setlightfreq(gspca_dev);
 
 	switch (sd->sensor) {
@@ -6905,19 +6849,14 @@ static int sd_start(struct gspca_dev *gspca_dev)
 
 	setautogain(gspca_dev);
 
-	/* start the transfer update thread if needed */
-	if (gspca_dev->usb_err >= 0) {
-		switch (sd->sensor) {
-		case SENSOR_HV7131R:
-		case SENSOR_PAS202B:
-			sd->work_thread =
-				create_singlethread_workqueue(KBUILD_MODNAME);
-			queue_work(sd->work_thread, &sd->work);
-			break;
-		}
-	}
+	if (gspca_dev->usb_err < 0)
+		return gspca_dev->usb_err;
 
-	return gspca_dev->usb_err;
+	/* Start the transfer parameters update thread */
+	sd->work_thread = create_singlethread_workqueue(KBUILD_MODNAME);
+	queue_work(sd->work_thread, &sd->work);
+
+	return 0;
 }
 
 /* called on streamoff with alt 0 and on disconnect */
@@ -7020,8 +6959,15 @@ static int sd_setquality(struct gspca_dev *gspca_dev, __s32 val)
 	 && i == qual
 	 && val < jpeg_qual[i])
 		i--;
+
+	/* With high quality settings we need max bandwidth */
+	if (i >= 2 && gspca_dev->streaming &&
+	    !gspca_dev->cam.needs_full_bandwidth)
+		return -EBUSY;
+
 	sd->reg08 = (i << 1) | 1;
 	sd->ctrls[QUALITY].val = jpeg_qual[i];
+
 	if (gspca_dev->streaming)
 		setquality(gspca_dev);
 	return gspca_dev->usb_err;
@@ -7071,6 +7017,7 @@ static const struct sd_desc sd_desc = {
 	.nctrls = ARRAY_SIZE(sd_ctrls),
 	.config = sd_config,
 	.init = sd_init,
+	.isoc_init = sd_pre_start,
 	.start = sd_start,
 	.stop0 = sd_stop0,
 	.pkt_scan = sd_pkt_scan,